The present invention relates to a mobile radio telephone, and more particularly to a location registration inhibition control apparatus for a mobile radio telephone and a control method thereof.
In the case where an user of a mobile radio telephone (hereinafter referred to as "telephone") moves over a location registration area consisting of a predetermined plural service zones, the telephone requests a base station to make location registration in order to reduce a period of time necessary for transmitting a signal from the base station to the telephone. Upon receiving a request for location registration from the telephone, the base station requests a control station to execute the location registration. The control station has a current location of the telephone stored in a location information storage station in response to a request from the base station.
In such location registration, when a telephone's user moves at a high speed by car or the like, the telephone is caused to frequently move between a plurality of service zones. As a result, the frequency of the location registration of the telephone is increased with such a problem that it gives a load to the control operation of the control station relating to the location registration.
In order to solve the above-mentioned problem, there has been known a location registration system disclosed in, for example, Japanese Patent Laid-Open Publication No. Hei 5-130019 published on May 25, 1993.
This location registering system is so designed that a telephone detects the signal quality of a received signal, and when the signal quality is deteriorated, it is judged that the telephone's user moves at a high speed. In the case where it is judged that the telephone moves at a high speed, for example, even though the telephone's user moves over a location registration area, the system inhibits a request for location registration from the telephone to a base station.
By the way, in the mobile radio telephone system used;. in Japan, a transmission dial number for calling a telephone is different between a short-range call and a long-range call. This is because the control station smoothly conducts accounting to a call side that calls a telephone (hereinafter referred to as "call side"). The call side, for example, dials 030 when making a short-range call equal to or less than 160 km, and dials 040 when making a long-range call greater than 160 km.
The control station calculates a distance between the call side and a called telephone on the basis of a location registration area in which the called telephone exists, and judges whether a call from the call side should be made by the long-range call or the short-range call. In the case where the call side calls with a dial "030" regardless of a fact that a call from the call side should be made by the long-range call, the control station announces a message "please redial with a dial "040"" to the call side. On the contrary, in the case where the call side calls with a dial "040" regardless of a fact that a call from the call side should be made by the short-range call, the control station announces a message "please redial with a dial "030"" to the call side.
Hence, in the case where the user moves to a location where a call cannot be made without a dial of 040 regardless of the fact that the user promises the call side in advance that he is at a location where a call can be made with a dial "030" which is the short-range call, the control station announces a message "please redial with a dial "040"" when the call side calls the telephone. This leads to such a drawback that the system informs the call side that the telephone's user has broken his promise with the call side.
In order to solve the drawback of this type, it is possible to turn off the power supply of the telephone. However, in this case, because the control station announces a message "the power supply of the telephone is off" to the call side, there is a possibility that the call side suspects that the telephone's user has broken his promise with the call side.